Thanks all for your reply.... Yes, I do have the leatest driver from AMD... and Yes, I did tried with V-Synec Off... I even tried to lower the resolution to 1024 X 768. Nothing works. I just register "steampowered" and posted my question there... Hopfully I can get an answer. If I ignore the black Stripes in the sky... the games still play pretty good and smooth.... I don't know what the hell is going on. But my machine ran okay with Microsoft Flight Simulator X. This is the first game I have this kind of problem on my machine.....
And yes, my video memories are share with the system memories... But I got 8GB in the system....